Juvenile Flagfin Angelfish (Apolemichthys trimaculatus)

The Flagfin Angelfish (Apolemichthys trimaculatus), also sold as the Threespot Angelfish, is a lemon-yellow Indo-Pacific angel with bright blue lips and a dark-edged anal fin. This one is a juvenile, which is the best age to bring one home: young flagfins settle in and take prepared foods far more readily than adults. As it grows, the dark eye bar and the black spot near the back of the dorsal fin fade, and it develops the small dark forehead spot that gives the species its "three spot" name. Care level is intermediate and temperament is semi-aggressive. Browse our other live fish and saltwater supplies to round out the tank.

Care Guide

• Tank size: a juvenile is fine in a smaller tank for a while, but plan on 125 gallons or more for an adult. Flagfins reach about 10 inches and want long open swimming runs plus plenty of rockwork to graze and hide in.
• Live rock: mature rock covered in film algae and microfauna gives it something to pick at between meals and helps it settle. A brand new, sterile tank is the wrong home for one.
• Water parameters: 72 to 78°F, pH 8.1 to 8.4, salinity 1.020 to 1.025, alkalinity 8 to 12 dKH. Keep nitrate low and water quality steady; large angels show stress quickly in a dirty tank.
• Feeding: in the wild this angel eats a lot of sponge and tunicate, so variety matters. Feed two to three times a day, rotating a sponge-based angel food like angel and butterfly frozen blends, Formula Two, PE Mysis, and dried seaweed on a clip. Soaking food in AngeLixir helps a picky eater.
• Acclimation: drip acclimate slowly and keep the lights low for the first day. Give it a few caves to retreat to while it learns the tank.
• Order of addition: add it after the peaceful fish are settled but before other large angels, so it is not the newcomer in an established pecking order.

Specifications

Compatibility

• Good tank mates: tangs, larger wrasses, anthias, rabbitfish, hawkfish, and other robust community fish of similar size.
• Other angels: one large angel per tank is the safe rule. If you want two, pick different genera and body shapes in a very large system, like a flagfin with a Juvenile Imperator Angelfish, and add them together.
• Corals and inverts: reef safe with caution. Flagfins are known to pick at LPS, zoanthids, soft corals, and clam mantles. A fish-only tank or a reef of hardy, fast-growing corals is the best fit. Leave out sponges and tunicates you want to keep.
• Avoid: very small, timid fish that it may push around, and aggressive fish like large triggers that will bully a juvenile.

Recommended Foods & Supplies

• SFBB Angel & Butterfly Frozen Cube, a sponge-inclusive staple
• Piscine Energetics PE Mysis
• Ocean Nutrition Formula Two
• Two Little Fishies SeaVeggies Purple Seaweed with a feeding clip
• Brightwell AngeLixir food soak
• CaribSea Moani Live Rock for grazing surfaces and hiding spots

FAQ

Will it eat prepared foods?
Juveniles adapt to prepared foods much more easily than adults, which is why we like bringing them in young. A varied diet with a sponge-based angel food keeps it healthy and colorful long term.

Can I keep it in my reef?
Maybe, with the right corals. It is likely to nip LPS, zoanthids, and clams, so it does best in a fish-only tank or a reef of tougher corals. It is less destructive than many large angels, but there are no guarantees.

Will the color change?
Yes. The juvenile eye bar and dorsal spot fade as it matures, and the body stays a bright lemon yellow with blue lips and a dark edge on the anal fin.

How big does it get?
About 10 inches as an adult, so plan for a large tank even though it starts out small.